Gibberellins are widely used in agricultural horticultural practices for the following purposes.
1. Fruit Growth and Parthenocarpy:
Increased yield (larger size) and better shape of grapes is obtained by treating the fruit bunches with GA. The GA treatment also induces parthenocarpy in the grapes (seedless fruits).
2. Delayed Ripening:
GAs delay fruit maturity and senescence in lemon, oranges and cherries. This helps in marketing and storing of fruits.
3. Increased Yield:
GAs also increase yield (fruit size) and parthenocarpic development in tomato and berries. Besides, GA treatment also causes broader and longer leaf formation in pea, bean, tomatoes, pepper, cucumber, lettuce and cabbage etc.
GAs help in the flowering of many long day plants.
5. Breaking of Dormancy:
GA treatment helps break dormancy in “seed potatoes” resulting in uniform crop emergence.
GAs have also been used in increasing synthesis of various hydrolytic enzymes such as α-amylase, ribonuclease and protease in aleurone cells of barley grams to improve the yield
In conclusion it may be said that GA, originally obtained from the cultures of the fungus Gibberella fujikuroi, is present in different parts of higher plants. It induces internode extension, apical dominance, breaks dormancy, increases dry weight brings about flowering long day plants even when kept in short day conditions and replaces vernalisation.